The present disclosure relates generally to a system for, and a method of, efficiently processing targets, such as bar code symbols, to be electro-optically read by image capture, and, more particularly, to processing the symbols as they are being moved past at least one light-transmissive window of a point-of-transaction workstation.
Point-of-transaction workstations employing imager-based readers have been used in many diverse venues, such as supermarkets, department stores, libraries, factories, warehouses, and like environments, for many years. Such workstations were often configured either as stand-mounted scanners each having a window; or as vertical slot scanners each having a generally vertical window; or as flat-bed or horizontal slot scanners each having a generally horizontal window; or as bioptical, dual-window scanners each having both a generally horizontal window and a generally vertical window. Such workstations were often operated to electro-optically read a plurality of symbol targets, such as one-dimensional symbols, particularly Universal Product Code (UPC) bar code symbols, truncated symbols, stacked symbols, and two-dimensional symbols, as well as non-symbol targets, such as driver's licenses, etc., the targets being associated with, or borne by, objects or products to be processed by, e.g., purchased at, the workstations.
A user, such as an operator or a customer, slid or swiped a product associated with, or bearing, the target in a moving direction across and past a respective window in a swipe mode, or momentarily steadily held the target at an approximate central region of the respective window in a presentation mode. The products could be moved relative to the respective window in various directions, for example, from right-to-left, or left-to-right, and/or in-and-out, or out-and-in, and/or high-to-low, or low-to-high, or any combination of such directions, or could be positioned either in contact with, or held at a working distance away from, either window during such movement or presentation. The choice depended on the type of the workstation, or on the user's preference, or on the layout of the venue, or on the type of the product and target. Return light returning from the target over a large working range of distances to the imager-based reader was captured by a solid-state imager in one or more images over a field of view, and then processed, and, when the target was a symbol, was decoded, and read, thereby identifying the product.
Although generally satisfactory for their intended purpose, one issue with such known workstations involved the fact that if the target was swiped very quickly across the window, then the target might only remain in the field of view of the solid-state imager for just one frame. To reliably capture such an image over a large working range, the solid-state imager was configured to capture the image with a high bit depth, e.g., greater than eight. Some imagers can capture images with 9, 10, 12, 14, 16, and more bit depths. The bit depth is the number of bits, i.e., digits 1 and 0, which are used to represent a tonal value or brightness of each pixel in the image. An 8-bit image, for example, is represented by 256 brightness values, and a 9-bit image is represented by 512 brightness values. Yet, images with bit depths over eight require a greater amount of processing power and time as compared to 8-bit images, thereby often slowing and degrading the reading performance.
Accordingly, there is a need to enhance, and to render more efficient, the overall reading performance of imager-based workstations.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and locations of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The system, workstation, and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.